问题
I need to know if it is possible to start using the latest version of EF (4.3.1) with VS 2011 without having to install these CTP components as stated here.
I had these components installed but I removed them and since then I can't add a new edmx file to .net 4 targeted project; it complains about missing reference to System.Data.Entity.
Do I need to re install VS 2011?
回答1:
After I removed and reinstalled Visual Studio, I still couldn't get red of the error, so I used process monitor to log what Visual Studio is doing with System.Data.Entity as a path filter, turned out that Visual Studio was reading from
C:\Windows\Microsoft.NET\assembly\GAC_MSIL\policy.4.0.system.data.entity v4.0_0.0.0.0__b77a5c561934e089\policy.4.0.system.data.entity.config
which had binding to the
System.Data.Entity.dll v 4.2.0.0
once I cleared the file VS was worked like charm.
The CTP uninstall left this out.
回答2:
Yeah should work with no issues using .net 4, however theres a list of known issues when using .net 4.5. You dont need to re-install vs to get version 4.3.1 of entity framework, simply install it from the nuget package gallery and if you are using .net 4 it all seems to just work.
Issues listed when installing EF4.3.1 on .net 4.5 include those listed below.
Known Issues with Entity Framework 4.x and .NET Framework 4.5
Entity Framework 4.1 thru 4.3 included additional data annotations in the System.ComponentModel.DataAnnotations namespace in the EntityFramework assembly. In .NET 4.5 these annotations were moved to be part of the .NET Framework in the System.ComponentModel.DataAnnotations.Schema namespace of the System.ComponentModel.DataAnnotations.dll assembly. If you are using EF 4.x and targeting .NET 4.5 this results in two data annotations with the same name in different assemblies. Because the annotations in the .NET Framework are in a different namespace we were not able to use type forwarding to avoid this conflict.
It is possible to use EF 4.x on .NET 4.5 but we recommend using the latest pre-release version of EF 5. If you are not using the affected data annotations there is no impact on your code. If you are using the data annotations in a C# project you can use the extern modifier to ensure your code uses the annotations from EntityFramework.dll (http://msdn.microsoft.com/en-us/library/e59b22c5(v=VS.80).aspx). If you use the new annotations from the System.ComponentModel.DataAnnotations.dll assembly in .NET 4.5 they will not be processed by Code First.
The affected annotations are:
- Column
- ComplexType
- DatabaseGenerated
- DatabaseGeneratedOption
- ForeignKey
- InverseProperty
- MaxLength
- MinLength
- NotMapped
- Table
来源：https://stackoverflow.com/questions/9652914/ef-4-3-1-with-vs-2011